Gear-cutting machine.



1. G. RIMMER.

GEAR ICUTTING MACHINE.

APPLICATION FILED DEC.26| 1912.

Patented M311. M1916.

8 SHEETS-SHEET Y 1 l l ATTORNEK 11G. 111111111111. GEAR CUTTING MACHINEAPPLICATION FILED DEC.25. 1912.

Patented Mar. 14, 1916.

S SHEETS-*SHEET 2. l

www 11., L Im., Mwva, @v f "0. O 1Mb., l, ,1\\ IT s w@ 1M INVENTOR.' 1James /mmmt wf r l WHA/5555s.

GEAR CUTTING MAcHiNE.

APPLICATION FI'LED,DEC.26.1912.

111191111111 Mar. 14,1916.

'8 SHEETS-SHEET 3.

Jar/zesV Gi/zmezft 1:11 .1 TTORNEK 1. (i. RIMMER.

GEAR CUTTING MACHINE.

' APPLICATION man 050.26.' 1912.

WITNESSES: l INVENTOR.

J. G. RlMMER.

GEAP. CUTTING MACHINE.

APPucA'ior.- mm 010.26. 1912.

1,175,814. Patented Mar. 14., 1916.

8 SHEETS-SHEET 5.

[NVE-NTOR.

A TTORNE Y.

1. .G. RIMMER.

GEAR CUTTING MACHINE. APPLICATION FILED 0126.26.1912.

Patented Mar. 11, 1916.

8 SHEETS-SHEET 6- I 64a. y VVENTR.

B Y @wi dimes. @H/7272267.

J. G. RIMMER.

GEAR CUTTING MACHINE.

APPucATloN FILED Dc.2. 1912.

Patented Mar. 14.-, 1916.

8 SHEETS-SHEET INPI'ENTOR. di/zes Z2 fijan mez WJINESSES.- y

ATTORNK 1. G. RIMMEB.

GEAR CUTTING MACHINE.

APPucAnoN man DEc.26, 1912.

Patented Mar. 14, 1916.

INVENTOR.

Jczmcs @Himmel v WHNEssEs.-

Lg, A TTQKNEY.

@y f2 New lfoijfollr Downs,` ""Norfollii and State of. Massachusetts,have and requiring elaborate computation or ref.- f

".Beitylznown that .laines G.`R1Miin n, of Quincy,y in the county ofinventedv` certain newzand usefuh improve-` .vil.mentszvin GearaCuttingMachines, of wliicl" th following is a specification? yfinvention`relates to gear cutting niachinesof tlie'type wherein the gear teeth arecutloyiageneratingiaction ivit'ha definitely movement o'f the 4bobbingcutter or iitting means relative to thefwork. y y y lVhile` adaptedforgeneial geareutting y uses ftheinventionis` more particularlydesignedjfor cutting worm gears. spiral gears `and the `various kinds ofhelical gears such l n sfedlin. automobile drive trains. y `1jiOneyofltlie prime `obfects of the invention "is tofprovide asimple andeffective machine adaptedato..produce Hindley or hour-glass i y gea"'ithafeed movement betweenltlie tool jerk in aradiall direction thereto,or imple shifting of connections without for" helical gears,v with theworin meinben blank .oecupying i a position which the hobuisuallyoccupies and Wiseeedimpartedthereto. f Ayfurtherobject of theinvention is to `pro- Videla@` machine arranged to permit any de--siredgcliange in the driving and i feed .ratios f offhthel .Cutter andblank'to be niadel easily "and quicklybya simple ,Change in a single.@drivingwgear tlaiii` without `.reau iringthe ``"emplfoyinent. of adifferential. `or jaclgin-the-v` ox,.zoruliliie expedients usuallyresorted to,I

`.hav-ilus endere y y "-A. f rther object of the invention istoiproi vidaniachine,wherein the `lilanlris-lield up `toathe.ciitteii'-u'ith aconstantly actingpoifverfulsiiringir 'like iin-essure insuring even,. isteady" action in cutting'. with the'eliinina- `the iuinping andcliatterinawliich is y y y y `serious diiiticulty` in tlie cutting, asin `the cutting of lflindlev lgears. y i l YAfurtherobjectof theinvention is to-proeytoaiilinvolved table. y y

lthe working parts, La requisite change speed device andcontrolsasseniblage\` of parts to produce Worm" UMTEDSTATES PATENTonrion.

i GEAR-CUTTINQMACHINE.

Patented Mar. ist, 1916.

i Application ledbecember 26, 1912. Serial No. 738,765.

vide a. simple, and easily and conveniently operable means foreffectingy slight relative adjusti'nents between the cutting member andblank while these are in operative positic-ii to take a small excess cuton one sideo-f the teeth if desired, or to set the hob more centrally orotherwise.

A still further object of the invention is to provide driving geartrains and operative connections ot' a simple and powerful type to theseconnections. having ling means easily and conveniently operable. Theabove and other obiects and features l, of the invention will be betterunderstood from the following detailed description taken in connectionwith the accompanying drawings and will be thereafter pointed out in theappended claims.

`Referring to the drawings, Figure l is a. horizontal, section takengenerally along the line 1 1 otFig. 2; Fig. l is a detail cross section'of a shaft construction shown 'in Fig. l; Fig. 2 is a side elevation ofthe inachine;l Fig. 3 is a plan view of the machine l without the hob;Fig. l is a lengthwise Vvertical section generally along the line -t ofFig. 3; Fig. 5 isan end view of the machine Fig. 6 is a transversesection along the lintl 6 6 of Fig. 3; Fig. 7 on line'7-7 of Fig. 4showing the spring pressing elements; Fig. 8 is a, transverse Vsectionshowing the work table and its controlling connections on line 8-8 ofFig. 3; Fig. 9 is a fragmentary view partly in elevaticn and partly invertical section showing the manner in which the spring pressing meansacts on'the table; Fig. 10 is a view fi'cinbeneath of the parts showninFig. 9; Fig. 11 is a fragmentary elevatioiishowing the drivingconnections for the table operating and `screw cooperating controllingmechanism; Fig. 12"'is aview similar to Fig.

r`1l .but showing the parts in position for tripping an `automatieallvoperated disconnecting clutch; Figs. 13, ltand l5 aredetail viewsshowing the construction of the clutch operating arm moved by the gearsshown in Figs. 1l and 12;Fig. 11G is a detail elevation showing themounting of the change gears which govern the'` relative kturning movements of the blank and cutter: Fig. 17 is a traiisverse'section thereofon line 17- -17 of Fig. `16; Fie". 18 isa central section online 18;; 18of l" l. showing the main change speed box :from the prime driver; Fig.19 is is a horizontal section yarriend vieiv showing adetail of a shaftconnection. in Fig. 18; Fig. 2() is a section on line 20-20 of Fig. 1;Fig. 21 is an enlarged section'oniline' 21-21 of Fig. 1; Fig.` 22 isa'.detail of a clutch operated lever shown in Fig. 21'; Fig. 23 is afragmentary View The bed and supporting rthe machine designatedgenerally 1 has horizontalA slide Ways 2 formed along an\ partly in planand partly in section of the parts shown in Fig. 21; Fig. 241s a.fragmentary view partly in plan and partly 1n seetiou.- showing themeans for moving thev hob endwise; Fig. 25 is an' enlarged 'detailsection Vshowing a hand Wheel connection for controlling anddisconnecting the clutch to the hob' feed; Figs. 26 and 27 shov'vf-saidhand wheel vin elevation and 'plan respectively; Fig. 28 is an end viewtaken in section on line 28-28 of Fig. 1; Fig. 29 is'. a detail section.showing a part of the feed'igearhange; Fig. 30-is a partial planvievvshow-A ing diagrammeatieally the manner in which the ciitternttacks Atheblank; Fig. 31 is" a view similar to Fig. 7 showing a modied formwherein Weights are used instead of springs; 'andFig 32 is a verticalsectionof the form shown 1n Fig. 31. a y frame workof upper portionthereof on which is guided the slide carriage 3 inwhich the Work table 4is journaled in intertting relation'as best seen inFig. 4 and held inplace by a. removrlble'plate 5'. 1 Thisslide carriage is shown as formedasI an upright tubular housing which lncases a spiral drive gear 6 shownlas integral with the workA tableand extend'- ing downward therefrom.The drive gear 6 is in driven engagement with a coperating spiral gear 7which .pis carried by a housing 8 having ends engaging the ends of thegear so that it is irioved endivise thereby and the housing 8 is'fittedfor sliding moveH ment in4 parallelism with the table movee mentonfivays 9 lformed on a front ange facing 10. shown as integral with thehousing 3. The gear'7 is keyed to a shaft 11 which has at its vinner endan end thrust collar itted'in hearings carried by the housing 8 asseen-'at 12, and the'oiitei end of `this shaft has long splines oi" key"ways 13 formed thereon rv'for driven engagement with cooperatingfoi-iiiatioiis in ahollow drive sleeve -14- whicli is jr'iiiriialed inhearings 15 journaled :onf'abolt 18 carried by a pair radius ariiisQO.r'19, 3ouriialedrespectively'iny bearingso'it thel traine ii'oikconcentric iii'th those ril-the geur 1li` andthe i'li'iving gear ofthemachine 'traine work and has keyed thereto'zti-driving gear 16; The gear16 is the driven?iiieiiiliei"of ati-ain of change gears'fh'gfiving"asshown an intermediate 17 21 of the train. The construction otliese 1radius aiiii's liest shown in Figs. liland l 17. they 'havingsplitelainpii'ig ends 22V ladapted to be drawn'togetlierby screwl bolts'23 to grip them fixedly to their respective hearings. TheY axis bolt 18,which is threaded-into a nut 18 set into the arm 19, and passes througha long slot 24 in the arin 2O is adapted to further insure the rigidholding` offthese arms with anintermediate 17 of any selected size inoperative position,

or a plurality of these intermediates ifdesired. The gear 21 is keyed ona shaft 25 journaled in the frame Work and thisshaft has keyed thereon aset of change gears 26 ofvvariedsizes in a gear box on the frame, thesegears 26 meshing with Aa coperative series-of gears 27 mounted vona'd'riving shaft 28 .and selectively engageable therewith byian'lendwlse movement which.l brings 1t into,

keyed relationtoI rany desired one of said gears as best seen in Fig.`18, this endwise movement 'being 'effected by ai circular rack formation29 at the inner end.l of saidshaft engaged with a pinion 30 carried ybya Vertically extending hand `operated shaft 31, the pinion 3() and rack29 being inclosed in a suitable housing 32.' The gears 27' asshown are'nested Within one another by soY flange collars at one side of eachfittingintoa recess 4seat at the adjacent side of the next and the endones of these gears have collar bearings in the gear box so that theentire series have in effect, bearing support independent of the shaft28 with which they are adapted to be brought in driven engagement. Theshaft 28 has slidably keyed thereto a driving .bevel pinion 33 actuatedby a bevel pinion 34 on a transverse shaft 35 which is the prime, driveshaft of the machine lbeing suitably journaled in brackets 'extendingfrom one end of Ytherame work and having fixed thereto a'beltv'gwheel 37or other operating-means Q l A p The shaft 25 supplies operative impulsefor rotating, the hob carrying spindle and also for effecting the feedof the Work table inand out radially relative toY thevhob when cuttingHindley gears or other gears inthe same nianner,.and this shaft alsosupplies f impulse for feeding thehob endvvise and simultaneously movinglt-he'gear member 7 eiidwise when the machine is Working under suchprinciple nl' operation. For rotating the hob spindle, the shaft portion25 which is substantially an extension of shaft 25 has f keyed thereto aWorin 38 in driving engagef nient with a worin wheel`39 formed with ajhollow sleeve 4() having bearing in the frame Work. rlflie hob jspindle.41 has slidably splined engagement with this sleeve so that it 'may bemoved in and out to etlect an endvvise movenrient'ofv the 'hobtangentially of the Wheel blanln This 'endivise sliding moi'enientof theAbob spindle 41 is eii'ected by li'avin'ga 'sleevetbeariig 42 oi asliile block 43' tittedbetween ollarsfixe'rlly carried by the hobspindlei` 'The' slide` bloekf43 -Which tliiis'carries-the-f'liob, bymeans of'v the sleeve rame n, operative posi# g t' guided @herepositively" vorml Wheel Shaft 455 ybear gfs, this` [shaft i 'by @gearingwand` Setiof ohange lgears The quired l but l siiaiaggtsehaci vpetable"foyE an mail? mman` n n i 26 and 27 to show n parts.` `Itwillfbe seen that the inturned the'hand Wheel inem assembled j1no `endof shaft 73 e also `has' its 1o its otherend enga vWork table.'

`formed to hoi movement and is Iitself mou 'movement kto swing the Worin4Blintoand n Aont `oi. engagement with the l, by theactiiation of ahandle 89 t bracket up and down.

jhandie 89 the tableiee or out as requirefh an "ranged so that# tributesto insu of the `Worm when it i at the end of a screw @intern drivesgearl 9.7

whichfis the inatebf the shaft other side'of fffhavetheir innerl orright 4hand endsas' ""s'seel'iinFig. 7 provided with thrust "99 toresist ieifthand endwise movement as "seenv saidigure and they centfeedhaf-t hf "buter orvnieft t thereof LjO-ihe ieieeve'' fjou'rnaled insuitable bearings on the frame work having keyed engagement ivith theshaftfpermitting sliding of` said shaft therethrough; `The shaft 73 isequipped venting' endwise `movement of the shaft 73 'Mireiative`thereto; The clutch collar 7 6 is controlled by a rhand Wheel 79threaded on the s1eeve`77 and havinga turned in flange `engaging theCollariniike `manner as the Harige 52,` reference being had to Figs. 25,the construction of these flange is eut away on one side as at 80 sothat n bei" is capable of being perative relation with the It will alsobe noted that the Xtending out through the end of the `sleeve 77 issquared as at 81 'to receive A"a crank or llike ing thesamejby hand w ilThefworin69 which has the Worm Wheel in drivenengagenient therewithabove,

Wer part in driving engagementwith a 'Woiin'iwheel 82 ixed on ashaftSBIwhieh` extends downward and crosswise of the finaohine with a Worm 84fixed near ging a Worin wheel' 85 constituting the driver `for the 'feedof the The shaft 88 has its end which Worinwheel 82 journaled in abracket 86 pivotaliy monnted concentric `Wi;h"t1ie worni69`as Seen at'S7. Its 'other end is journaled in a bracket SSWIiieiris d the worm 84from endvvise nted toffhave clutch collar. i

hen desired.

carries Vthe Worin yWheel` 85 hich con-` mv-ingjthe Thus by taning thetrois an eccentric device for d the parts -are arthe action of 'gravityconite the complete throwing out s not turned into full The 'worin'wheel 85 a. pinion 91 journaled ging a gear93 fixed shaft 94, this`gear at the end of the 9G which gear 95` .on a screw shaft n 96% yatthe shaft 96. The shafts 94 and inoperative position.

on a tnd 92 and enga driving `a gear 95 fixed main feed screw shat,

bearings hand end to resist movement Screivfhas a Small `capability of`endwise i'inleinent for turnd may be thrown/in right, t,beingnoted thatthisY i iso 1.

ioc

ral main a thrust bearings at its,

'movement inthe opposite direction, 91. e., to the left in Fig. 7 aspermitted by the spacing away of the gear 95 from,the adjacent bearingcollar 101 and as provided for by the extended collar 102 inclosing thethrust bearing 100. the main feed shaft 96 engage a nut 101 fixedlydepending from the work table slide cai-ringe 3 and this and the screwrods 91, 98 extend through passages 105 provided therefor in a pressuretransmitting block i106 also xed to the work table slide carriage 3. Asseen in Figs. 7, 8 and 9 the The threads 103 onV screw r'ods V91, 98have fitted on the threaded portions thereof nut blocks 107, theseblocks being held against rotation, by having depending lips 108 engagedrby bars 109 fixed to and extending back from the bottomof pressuretransmitting block 106. Interposed betweenthe l,hacking nuts 107 and thepressure transmitting block 106, and encircling the rods 91, 98 arestrong coil springs`110 which react against the pressure transmit-vfollow up the block 106 as it is moved alongl with the carriage by theaction )of the threads 103' of rod 96 von the nutlOf, so that thesprings 110 will maintain a substantially constant compression andpressure action upon the table. Thus the thrust bearing 100 at theinner'end of rod 96 is kept engaged by the spring pressure transmittedthrough the nut 104. and vtending to move 'rod 96 outward or to theright as seen in Fig'. l. The mounting of the rod 96 for simili endwiscmovement not only is a feature of this resilientvspring .feed movementbut it also is utilized for operating an automatic throw outlmeehanismin a manner to be presently described.

- In Figs. 31 and 32 I show av modified form of the constant pressurefeertnieehanism' typified by tie springs just described and in this forminstead of having'lsprings in-l terposedbetween the nuts 107 and theblock 106, I interpose between these, members".

spacing tubes or collars 111 and provide the c onstant pressureuponthework table by a heavy weight 112 carried bythe long arms 113 of bellcrank levers' having, a fulcrum.

hearing at 114k inthe frame work and `with their short arms 115 pressingagainst bearings 116 `at the ends `of the rods 94', 98. With each of theforms described, as'` the work table is allowed to "move forward by theturning of feed screw rod 96, the Vtable and the work carried therebyare urged forward for the working cutsy with a steady powerful pressurethat eliminates the jumping and chattering which is often a seriousdiliculty as in the cutting of Hindley gears.

lt will be observed that with each of the described forms the constantpressure ele` nient whether spring or weightgremains insubstantiallyfixed relation 2'.. el, extent of y compression of thesprings is not Varied, and when the weightis-used it remains in anapproximately constant position. and does not require any large spacefor its housing. The limit of forward feed movement of the work table isdetermined by amici-ometer stop device consistingV in a stop pin 117removably set into a. Vclamping seat'118 proas is usual@v With thisconstruction of stop pins 117 selected of 'suitable lengths'for diflferent sizes of gears to be cut may be provided and a properly selectedone of these for any"particular size of gear may be inserted in theclamping seat 118. Then by adjusting the coperating stop pin 119 by themicrometei' device, the depth of eut to be made can be determined with.precision and willvb'e exactly thesame for all gears cut with the sameadjustmeht. i. j

To provide an automatic stop for the feed when the table has reachedtheend of its working feed movementl provide the `following mechanism:When the table feed is stopped bythe stop pins 117, 119 coming together,the further'turning ofithe rod 96 by the feedvdriving-mechanism willcause it td move endwise inward or to the left in Fig. 7 carrying withit its `gear 95 as seen in Fig. 12. A vertical rock shaft 125 is mountedin position- -softhatqa'n 4arm 126 fixed thereto will-'engage the innerface of gear 95. Thus asf thergea'r 95 is `moved .in by the endwisemovement of rod 96the shaft 125 is rocked and in turn moves a bell crankgraduations 123 readablein connection with the stationary piecev121Vlever 127 fixed to the top thereof which through a connectingrod 128operates avb'elly crank lever 12,9. pivoted tothe frame Work at` 130with-'a spring 131 normali holding the parts so httlthe arm 126is he dpressed aginst the ear 95.. Thegotlier arm-.of bell crank-.lever 1 itis,connected to 'operate a 'harz 132 whichhdsits extremity 133 inposition-v to vnormally holdI down sy lvertical slide lbar 134 whichisc'onnectid to one arm of a bell crank lever -135pivoted at'136, theother armthat controls' the drivinglconnection tothe .137 ofwhich'engages the clutchcollar 57 `11,175,814n 1 Si wparts in positionfor rendering active any selective one of thefeed changes.Theverticalshaft 31 which controls the speed change gears`26, 27 of theinitial driving p active the proper connection for the desired speed. l

is to be observed that the construction of the i frame Work andmounting'parts of my ma# `chine is specially designed with a` view to iy `economical manufacture and convenient asy edivhen the-` y y p ydwviselfemtape "dChob QF this purpose `is formed plane with a straightedge along hebellfera'nlcley y 29 Ls pivoted to u its sideas seen in.152 andthe severalmounti ted to extend ing and housing brackets 153,154, 155, etc.,

`iehob. 1 This rod are secured thereto in proper relative positrain, hasat-itsV upper end an armfla 70 carrying a spring pressed pin 31"`copera- `tive with seats 1n a. disk 31c for rendering i y Referringespecially to Figs. 1,2 and 4 `it 't5 sembl'age.` The body or frame baseproper 80 i for`-engage tions by suitablebolting. Likewise the top l85`y y y y y of the bed frame on which the slide ways 2 ing-set tojoperuare formedis'plane with a pedestal-156 se-` "mrnechanismfdecured `atitsend forsupporting the slide i bfhas been fed Ways 45 on which the hobcarriage 43 is quisitejeitentffor completv` guided. The i arrangement oftheprime 90 fixedlstopyhiis carried at driving shaft 35 -on brackets-crosswise of Wto preventexcessive the machine at one end thereof,` withthe `change gears connecting the lengthwise extending parallel shafts11, 25 exposed atthe` ,.compactnessfoi'lthe organization, andI easy 1accesslbility ot the parts requiring frequent adjustment or change. Inthis connection it is to ,be noted that not only are thefchange changegear train 58 which requires to be y properly selected for the size ofthe gear to "end of the machine ,over shaft 35, makesfor 95.

y gears 16, 21 which determiney the driving 1.00 i ratio of the gearstobe cut, thus easily accesl m"msibleiatthe end of the machine, but theother y 5 by a slid-I be' cut, is also in an easily reached position.105 L 5orltion25 has Considering first the principle ofv operanoyeinentcarrying tion and manner of use of theinachine when "the work table isfed radially toward the hob,` it is to be understood that for thisuseWorktable feed line and the clutches 50 and n 76 disconnected so thatthe hoh is held from y kendwise movement by the stationary screw .nfexternally .'46 and the spiral gear 7 is also stationary the hob is setsubstantially` central of -the 110 "engagesinternal relative tothe worktable. A` micrometer 115 50;,hav1ng a stastop pin 117 is now selected of"approper "ne j ,Thecol-V `length with reference to the size 'ofthe geari 5l atl its end `to `be cut and the micrometer head 122 is adntbyhand,i justed to set the stop pin 119 to determine thehob can with precisionthe depth of teeth desired. 121.0

jperating de-` 1 The ehangegeartrain 16,117, 21 is. selected gegears forwith reference to the number of teeth to `loe 64g@ carried `cut in theblank and in this connection it iousedand may be notedthat I preferablyform the handle-640 lspiral gear 1nember,"6, 7 and connecting 125ieldihgly holdihe like driving gearing is something neara 1 139 gearratio becomes 10)(3 or 30:33 Which is the proper ratio for the teeth inthe change gears. As these numbers would make the gear wheels smallerthan desirable they may bemiiiltiplied bv 9 or the teeth in gears 21, 16may be 60 or. 6G respectively. In like manner supposing gearing in theratio 7:38 is to be cut, 7 3=211z33 and multiplying thisl ratio by 2 tomake the gear ivheels of convenient vsizethe gears 21, 16 will have 4Qand 7G teeth respectively. lVhen the gear Whether a Hindlev orordinary-one as required is completed from the blank .the microiiieterstop pins 117, 119 comingl together,

'snlined shaftl 1 1, sliding` lstop the table movement and therefore thecontinuance of the feeding drive moves the central feed screiv rod 96endivise to the left in Fig. 7 causing gear 95 to swing arm 126 andthrough the described connections throiv out the clutch G7 in the'feed=train, and thus stop the feed. 1t will Ebe understood that thefeed movement may be regulated as desired bv the change gears 63, 65 inthe feed train, and that the feed is in reality at all times that of thepov'verful springs 110 'or the Weight 112 which act to press the blankwith an even, strong and steady pissure to the cutter which is a featureof great value and importance particularly in Hindlev gear cuttingvWhere it is necessary7 to minimize the chattering and jumping effects.`,In this feeding operation the spiral gear 7 moves-along with the gear 6which it drives but `without endvvise movement relative thereto` thescrew' 74 being stationarv and its splined shaft 73, as also the sleevebearings. l

Taking up noiv the second principle of operation Wherefor mv improvedmachine 4 neou'sly'fed endwise. the gear 7 then acting is adapted, viz:that of cutting gears With an endwise fed tapered hob which is oftenadvantageous and practicable the hob on its carriage 43 and the spiral.gear 7 on its carriage 3 are for this operation simultaon the gear 6which it drives not onlv by its turning movement but also acceleratingits movement with an action of a rack thereon and thus turning the blankwith an accelerated coinpen'satiiig movement which corresponds to theendwise feed of the hob and causes the hoby teeth to attack the blankthrough theirproperly throughout Vits range of endvv'ise move-ment. Forthis purpose the clutches 5t), 76 are throvvn in so that the screws 46and 7l which feed the hob carriage d3 and the spiral gear carriage 3,Aare driven.

These screivs and their driving worm gearing are preferably made alikeso that in order to effect a proper endivise feed. of the hob, havingreference to the relative size of the blank being cut and of the spiralor worm Wheel t5 it is only a matter of proportioning the change gears58 so as to attain adriving ratio'the same as that which the. [pitchdiameter of the worm Wheel to be cut bears to the ivork table Worm 6.For example, supposing that the table worm 6 have a pitch diameter of 15and that the Worm ivheel tofbe cut is to have a pitch diameter of 10;the ratio here being 15:10 or 15:1, the change gears 53 may have 60 and40 teeth respectively, or 75 and 50 or anv convenient number preservingthe same ratio. Supposing a gear is to be cut with a pitch diameter of 9the ratio ivill here be the Work table having been previously moved uptoproper position with a properlv selected micrometer pin 117 abuttingagainst pin 119. In this endivise feed of the hob thev short teeth atthe small, tapered end of the hob first attack the blank making a seriesof nicks .around the circumference thereof asindicated at ai. As the hobgradually progresses in its feed movement tangentially of the blank thelonger teeth gradually enlarge thecuts until the final depth of theteeth to be produced is attained as indicated at I). the hob thenoccupying a position indicated in Ydotted line-s at o. Thereupon as thecutting .of the blank is finished thevfinger 144 of hob carriage 43engages the stop 143 and throivs out clutch 67 in the manner described.lt will of course be understood that in this operation the screw driveshaft S3 is disconnected by "the drop of ivorm 84 out of engagement lioblank on `spindle and mounting cutting indicate the scope of theinvention. Having described my invention what 'I xclaim as new 'anddesire to Secure by LettersPatent is:` i i il. \A machine ofA the kinddescribed comprisingtwo carriers, one forholding a gear `"cutting meansand .the othera gear blank, means for effecting a power feed movementfof ksaid `carriers relative to each ,other in a direction radial of theblank, and nieansfor effecting a power lfeed movementl of the blankandciitterirelative toeach other in a "direction substantially,tangentialto one of them, saidtwo feeding nieansliaving provision for selectiveoperational; Will. 2. A machine of the kind described comprising twocarriages, one for a worin Wheel element and the other for a `Worinelement,

one of said elements being a blank and the other a cutter, means forrotating a gear i and cutter yin timed relatiommeans for powerfeedingthe carriage `of the Worm.

`Wheel element radiallyof a blankcarried thereby, and-means for powerfeeding the Worm element endwisethereofin a relation isubstantiallytangential of said worin Wheel "elementysaid'two powerfeeding ineans` hav# j ing provision for selective fopeiation at will.

a-ift` machine-of the kind described comprisingltwocarriages, one foragear cutter and the otherfoi. a gear blank, means for sil multaneolislyrotating a cutter' and blank "carried thereby inltiined relation, meansfor power feedingtheblank carriage 'to present theblank to the'cutterin` a direction radial `thereof and means for poweiwfeeding the nfcutter in aldirection substantially tangential "oftheblanlr, said twopowerfeeding means being selectively operative at will. y A machineofthe kind describedcomprising two carriages, one for a Worm Wheel elementand the other fora ivform element, one of said elements being a blankand the y `,other a cutter, means for power feeding said carriagesselectively at will, and mechanism forrotating a `blank and a cuttermounted on said `carriages in timed relation, said ne'clianisinxhavingan element `arranged to' actas ai rack for"controlling"therotation oftheiworm `Wheel `element to compensate for `the..movement of theworinelement as iindeparted by the power-*feed of` its carriage,`

A machine of the kkind described cbm- ``prisiifi',- i'acarriage mountedforsliding move ment, a `worktable,` niountedfor rot-ation thereon,means for pewer feeding said cai'- riage in' a direction radial of a`blank carried ,thereby and for rotating the blank, heb

spindle mounted to hold the hob in a relation substantially tangentialof a blank on said table, and means for power feeding a hob carried bysaid spindle endwise in defi* nite timed relation to the rotation of theblank, said means having provision for operation ivitli the'workcarriage. feed inoperative or vice versa.

6( A machine of the kind described coin4` prising a. slidably mountedcarriage, afi'vorl: table rotatably mounted thereon equipped .with aworm wheel, a Worin mounted on said carriage for engagement With saidWorin `wheel .with provision forseparate endwise 4iiiovement at Will, ahob mounted in substantially tangential relation to a blank on saidIWork table With provision for endwiee move merit, and means for movingsaid hob and saidvivorin endwise in definitely timed rela tion to eachother and to the rotation of the blank.

7. A machine of the kind described coinprisiiig a slidably mountedcarriage, a. work table rotatably moi'iiited thereon equipped with aworm Wheel, a worin inoiinted on said carriage for engagement with saidworin. `wheel with provision for separate endwise movement at will, aheb mounted in substantially tangential relation t'o 'a blank on saidWork table with provision for endwise movc ment, and like feed screwshaving provision to be rendered optionally inoperative forsimultaneously inovingsaid Worm and hob endwise, said screws beinginterconnected oy a change speed device and having provision for drivingconnection in definitely timed. relation to the rotation of the blankand lich.

8. A machine of the kind described coinrising a rotatably mounted Workcarrier, a ob spindle mounted inoperative relation thereto, a shafthavingV connections for ro- -tating the work table and having otherconnections ,including a worin for driving 'the hob spindle,` and' meansfor effecting a rela" tively fine adjustment of the hob relative to theWork.

9. Amacliine ofthe kind described com-- piising a rotatably mounted Worktable, a

rotatably mounted heb, intergeared driving connections for said Worktable and hob in- 1 cluding a worm and worin wheel in the drive l to thehob, and a threaded adjuster having provision for effectingy relativelyfine ad iis Y .I ment ofthe saine to definitely adjust the hob relativeto the work.

11. A machine the'kind described comprising a .rotatably mounted hob,'aWork table lvmounted for feed Imovement toward and from .the hob andradially'ofa blank carried thereby, and -a. micrometer stop device forlimiting/fthe feed movement of said table, .said device yconsisting inav pin-detachable and selective as 'to length for-different sized`blanks, Aand a coperative pin' having a micrometer headfa-nd'adjusterconnected therewith for determining the depth the teeth are tobe cut. ,ni l 12x A machine of the-kinddescribed comprising a. table bearing arotatably. mounted gear blank vcarrier having provision for powerfeed'movement toward vand from ythe cutter, a stop pin detacliablyclamped to said k table, said pin being selective to correspond withdifferent sizes of blanks, and a cooperative stop pin mounted on a fixedpart ofthe 'machine with a micrometer head and 'adjusting means adaptedto determine the depth of the teeth to be cut in the blank.

`A machine ofthe kind described eomprising a rotatably mounted blankcarrier,

4a rotatable cutter spindle and means for power feeding the blankcarrierrelative to' the cutter in a direction. radial of the blank,

'v there being interposed in said means a separate and automaticallyoperative device for pressing the blank'strongly, evenly and constantlyto the cutter to prevent chattering i .K "and jumping.

i4.. f a machine ,of the iena described fomprising a rotatably mountedWork-carrier, a rotatable hob spindle, and means for feeding saidcarrier'relative to'said spindle yin a. direction radial of a blankcarried thereby, there being interposed in said means a device havingself take-up `provision for pressing the workto the" cutter withacontinuously` acting movement, said take-up proi visioncausingsaidrdevice to iemainn substantially `the saine relation. to the feedthroughout the range of work carrier movement to effect a strong, evenpressure lin any position thereof. i '4 l 15. A machine of the kinddescribed comprising a carriage having a work table mounted thereon, acutter spindle. mounted in operative relation thereto, and means forinoviiig-said carriage toward said spindle,

said means consisting in a power driven feed screw mounted forsniall-endwise movement 1n a direction opposite toV that of the feed'and engaging a nut on said carriage, and a pair of. threaded shaftsy ateach side of said feed screw in gearedl connection to said screw, havingmeans coperative therewith for strongly and evenly pressing the carriagein the direction of its feed fin'ovenient, said means ybeing formed toremain in substantially constant operative relationthronghout the rangeof carriage movement. i

v1G. A machine of the kind described comprising a cutter holdenacarriage for a gear blankl mounted for movement toward and `from thesame, and means for effecting power movement of said carriagmsaid meansconsistingvin a .threaded-.feed shaft having power driving connectionsyand engaging a nut carried by said carriage, said shaft havingprovision for small endwise movement in a direction opposite vto that ofthe feed,l a pairfof threaded shafts at each side of said feed` shaft ingeared connection with said shaft, a nut engaged with eachl of saidpairl of shafts and held froijn rotation, backing *means fixed to saidcarriage, and springs encircling said shafts and reacting between saidnuts and said backing means to stronglyl and evenly press the carriagein the 'direction of its feed movement.

In testimony whereof I have aixed my signature, in presence of twowitnesses.'

JAMESy GORDON manana.

- 'Witnessest CLYDE L. Romains, LoUIsn JQRDAN.

